In the case of known sliding-rising roofs (e.g. DAS No. 16 05 960), the sealing of the encircling annular gap against the penetration of water when the roof is in the closed position presents considerable difficulties, in particular between the rear edge of the cover plate and the adjacent edge of the roof cut-out. The reason for this is the absence of the trough-shaped profile which is usually found on sliding-only roofs and which is fixed to the sliding cover plate and engages below the rear marginal gap thereof (German Pat. No. 15 55 555). In the case of sliding-rising roofs, such a profile would prevent the rising function, i.e. the pivoting of the cover plate out of and above the fixded roof area. The sealing profile usually provided in the marginal gap and consisting of an elastomeric material cannot prevent the penetration of water with the necessary degree of reliability, particularly since the most accurate possible parallelism between the rear edge of the cover plate and the adjacent edge of the roof cut-out and a specific gap width are required for this to be assured. Furthermore, symptoms of wear and tear and ageing are to be found in the marginal gap seals which adversely affect the sealing-tightness of the marginal gap.
A further disadvantage of all the known sliding-roof constructions resides in the fact that in the position of closure, the cover plate is not sufficiently secure against its rear edge lifting. Therefore, when forced or even during movement of the motor vehicle and as the result of a difference in pressure between the interior of the vehicle and the flow of air over the vehicle roof, the pressure inside the vehicle being greater, it is possible for the rear edge of the cover plate to lift outwardly.
Finally, in the case of the known sliding-rising roofs, the front pivot axis or hinge arrangement is so constructed that when the cover plate is raised, there is a broad gap between the front edge of the cover plate which dips relatively far down into the roof cut-out and the adjacent edge of the roof cut-out and this can lead to undesirable noise while the vehicle is in motion.